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Harripaul R, Morini E, Salani M, Logan E, Kirchner E, Bolduc J, Chekuri A, Currall B, Yadav R, Erdin S, Talkowski ME, Gao D, Slaugenhaupt S. Transcriptome analysis in a humanized mouse model of familial dysautonomia reveals tissue-specific gene expression disruption in the peripheral nervous system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.28.559870. [PMID: 37808686 PMCID: PMC10557663 DOI: 10.1101/2023.09.28.559870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Familial dysautonomia (FD) is a rare recessive neurodevelopmental disease caused by a splice mutation in the Elongator acetyltransferase complex subunit 1 ( ELP1 ) gene. This mutation results in a tissue-specific reduction of ELP1 protein, with the lowest levels in the central and peripheral nervous systems (CNS and PNS, respectively). FD patients exhibit complex neurological phenotypes due to the loss of sensory and autonomic neurons. Disease symptoms include decreased pain and temperature perception, impaired or absent myotatic reflexes, proprioceptive ataxia, and progressive retinal degeneration. While the involvement of the PNS in FD pathogenesis has been clearly recognized, the underlying mechanisms responsible for the preferential neuronal loss remain unknown. In this study, we aimed to elucidate the molecular mechanisms underlying FD by conducting a comprehensive transcriptome analysis of neuronal tissues from the phenotypic mouse model TgFD9 ; Elp1 Δ 20/flox . This mouse recapitulates the same tissue-specific ELP1 mis-splicing observed in patients while modeling many of the disease manifestations. Comparison of FD and control transcriptomes from dorsal root ganglion (DRG), trigeminal ganglion (TG), medulla (MED), cortex, and spinal cord (SC) showed significantly more differentially expressed genes (DEGs) in the PNS than the CNS. We then identified genes that were tightly co-expressed and functionally dependent on the level of full-length ELP1 transcript. These genes, defined as ELP1 dose-responsive genes, were combined with the DEGs to generate tissue-specific dysregulated FD signature genes and networks. Within the PNS networks, we observed direct connections between Elp1 and genes involved in tRNA synthesis and genes related to amine metabolism and synaptic signaling. Importantly, transcriptomic dysregulation in PNS tissues exhibited enrichment for neuronal subtype markers associated with peptidergic nociceptors and myelinated sensory neurons, which are known to be affected in FD. In summary, this study has identified critical tissue-specific gene networks underlying the etiology of FD and provides new insights into the molecular basis of the disease.
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Millar Vernetti P, Dalamo K, Khan Z, Gonzalez‐Duarte A, Frucht S, Kaufmann H. Meropenem-Induced Facial Myoclonus. Mov Disord Clin Pract 2023; 10:S21-S23. [PMID: 37636233 PMCID: PMC10448627 DOI: 10.1002/mdc3.13777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/10/2023] [Accepted: 03/22/2023] [Indexed: 08/29/2023] Open
Affiliation(s)
- Patricio Millar Vernetti
- Department of Neurology, Dysautonomia CenterNew York University School of MedicineNew YorkNew YorkUSA
| | - Kaia Dalamo
- Department of Neurology, Dysautonomia CenterNew York University School of MedicineNew YorkNew YorkUSA
| | - Zenith Khan
- Department of Neurology, Dysautonomia CenterNew York University School of MedicineNew YorkNew YorkUSA
| | - Alejandra Gonzalez‐Duarte
- Department of Neurology, Dysautonomia CenterNew York University School of MedicineNew YorkNew YorkUSA
| | - Steven Frucht
- Department of NeurologyFresco Institute for Parkinson's and Movement Disorders New York University Grossman School of MedicineNew YorkNew YorkUSA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia CenterNew York University School of MedicineNew YorkNew YorkUSA
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A novel ELP1 mutation impairs the function of the Elongator complex and causes a severe neurodevelopmental phenotype. J Hum Genet 2023. [PMID: 36864284 DOI: 10.1038/s10038-023-01135-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
BACKGROUND Neurodevelopmental disorders (NDDs) are heterogeneous, debilitating conditions that include motor and cognitive disability and social deficits. The genetic factors underlying the complex phenotype of NDDs remain to be elucidated. Accumulating evidence suggest that the Elongator complex plays a role in NDDs, given that patient-derived mutations in its ELP2, ELP3, ELP4 and ELP6 subunits have been associated with these disorders. Pathogenic variants in its largest subunit ELP1 have been previously found in familial dysautonomia and medulloblastoma, with no link to NDDs affecting primarily the central nervous system. METHODS Clinical investigation included patient history and physical, neurological and magnetic resonance imaging (MRI) examination. A novel homozygous likely pathogenic ELP1 variant was identified by whole-genome sequencing. Functional studies included in silico analysis of the mutated ELP1 in the context of the holo-complex, production and purification of the ELP1 harbouring the identified mutation and in vitro analyses using microscale thermophoresis for tRNA binding assay and acetyl-CoA hydrolysis assay. Patient fibroblasts were harvested for tRNA modification analysis using HPLC coupled to mass spectrometry. RESULTS We report a novel missense mutation in the ELP1 identified in two siblings with intellectual disability and global developmental delay. We show that the mutation perturbs the ability of ELP123 to bind tRNAs and compromises the function of the Elongator in vitro and in human cells. CONCLUSION Our study expands the mutational spectrum of ELP1 and its association with different neurodevelopmental conditions and provides a specific target for genetic counselling.
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Tolman Z, Chaverra M, George L, Lefcort F. Elp1 is required for development of visceral sensory peripheral and central circuitry. Dis Model Mech 2022; 15:275184. [PMID: 35481599 PMCID: PMC9187870 DOI: 10.1242/dmm.049274] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 04/20/2022] [Indexed: 11/23/2022] Open
Abstract
Cardiovascular instability and a blunted respiratory drive in hypoxic conditions are hallmark features of the genetic sensory and autonomic neuropathy, familial dysautonomia (FD). FD results from a mutation in the gene ELP1, the encoded protein of which is a scaffolding subunit of the six-subunit Elongator complex. In mice, we and others have shown that Elp1 is essential for the normal development of neural crest-derived dorsal root ganglia sensory neurons. Whether Elp1 is also required for development of ectodermal placode-derived visceral sensory receptors, which are required for normal baroreception and chemosensory responses, has not been investigated. Using mouse models for FD, we here show that the entire circuitry underlying baroreception and chemoreception is impaired due to a requirement for Elp1 in the visceral sensory neuron ganglia, as well as for normal peripheral target innervation, and in their central nervous system synaptic partners in the medulla. Thus, Elp1 is required in both placode- and neural crest-derived sensory neurons, and its reduction aborts the normal development of neuronal circuitry essential for autonomic homeostasis and interoception. This article has an associated First Person interview with the first author of the paper. Summary: Our data indicate that Elp1 is required in both placode- and neural crest-derived sensory neurons, and that it exerts comparable effects, including survival, axonal morphology and target innervation in both lineages.
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Affiliation(s)
- Zariah Tolman
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Marta Chaverra
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Lynn George
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA.,Department of Biological and Physical Sciences, Montana State University Billings, Billings, MT 59101, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
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Leonard CE, Quiros J, Lefcort F, Taneyhill LA. Loss of Elp1 disrupts trigeminal ganglion neurodevelopment in a model of familial dysautonomia. eLife 2022; 11:71455. [PMID: 35713404 PMCID: PMC9273214 DOI: 10.7554/elife.71455] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 06/17/2022] [Indexed: 01/28/2023] Open
Abstract
Familial dysautonomia (FD) is a sensory and autonomic neuropathy caused by mutations in elongator complex protein 1 (ELP1). FD patients have small trigeminal nerves and impaired facial pain and temperature perception. These signals are relayed by nociceptive neurons in the trigeminal ganglion, a structure that is composed of both neural crest- and placode-derived cells. Mice lacking Elp1 in neural crest derivatives ('Elp1 CKO') are born with small trigeminal ganglia, suggesting Elp1 is important for trigeminal ganglion development, yet the function of Elp1 in this context is unknown. We demonstrate that Elp1, expressed in both neural crest- and placode-derived neurons, is not required for initial trigeminal ganglion formation. However, Elp1 CKO trigeminal neurons exhibit abnormal axon outgrowth and deficient target innervation. Developing nociceptors expressing the receptor TrkA undergo early apoptosis in Elp1 CKO, while TrkB- and TrkC-expressing neurons are spared, indicating Elp1 supports the target innervation and survival of trigeminal nociceptors. Furthermore, we demonstrate that specific TrkA deficits in the Elp1 CKO trigeminal ganglion reflect the neural crest lineage of most TrkA neurons versus the placodal lineage of most TrkB and TrkC neurons. Altogether, these findings explain defects in cranial gangliogenesis that may lead to loss of facial pain and temperature sensation in FD.
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Affiliation(s)
- Carrie E Leonard
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
| | - Jolie Quiros
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State UniversityBozemanUnited States
| | - Lisa A Taneyhill
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
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Jacot-Descombes S, Keshav N, Brosch CMS, Wicinski B, Warda T, Norcliffe-Kaufmann L, Kaufmann H, Varghese M, Hof PR. Von Economo Neuron Pathology in Familial Dysautonomia: Quantitative Assessment and Possible Implications. J Neuropathol Exp Neurol 2021; 79:1072-1083. [PMID: 32954436 DOI: 10.1093/jnen/nlaa095] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Von Economo neurons (VENs) and fork cells are principally located in the anterior cingulate cortex (ACC) and the frontoinsular cortex (FI). Both of these regions integrate inputs from the autonomic nervous system (ANS) and are involved in decision-making and perception of the emotional states of self and others. Familial dysautonomia (FD) is an orphan disorder characterized by autonomic dysfunction and behavioral abnormalities including repetitive behavior and emotional rigidity, which are also seen in autism spectrum disorder. To understand a possible link between the ANS and the cortical regions implicated in emotion regulation we studied VENs and fork cells in an autonomic disorder. We determined the densities of VENs, fork cells, and pyramidal neurons and the ratio of VENs and fork cells to pyramidal neurons in ACC and FI in 4 FD patient and 6 matched control brains using a stereologic approach. We identified alterations in densities of VENs and pyramidal neurons and their distributions in the ACC and FI in FD brains. These data suggest that alterations in migration and numbers of VENs may be involved in FD pathophysiology thereby supporting the notion of a functional link between VENs, the ANS and the peripheral nervous system in general.
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Affiliation(s)
- Sarah Jacot-Descombes
- Nash Family Department of Neuroscience.,Friedman Brain Institute.,Icahn School of Medicine at Mount Sinai, New York, New York; University Center of Legal Medicine, Lausanne - Geneva, Geneva University Hospitals
| | - Neha Keshav
- Nash Family Department of Neuroscience.,Friedman Brain Institute.,Seaver Autism Center for Research and Treatment
| | - Carla Micaela Santos Brosch
- Nash Family Department of Neuroscience.,Department of Mental Health and Psychiatry, University Hospitals and School of Medicine Geneva, Switzerland
| | - Bridget Wicinski
- Nash Family Department of Neuroscience.,Friedman Brain Institute
| | - Tahia Warda
- Nash Family Department of Neuroscience.,Friedman Brain Institute
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, New York
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, New York
| | - Merina Varghese
- Nash Family Department of Neuroscience.,Friedman Brain Institute
| | - Patrick R Hof
- Nash Family Department of Neuroscience.,Friedman Brain Institute.,Seaver Autism Center for Research and Treatment
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ELP1 Splicing Correction Reverses Proprioceptive Sensory Loss in Familial Dysautonomia. Am J Hum Genet 2019; 104:638-650. [PMID: 30905397 DOI: 10.1016/j.ajhg.2019.02.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 02/08/2019] [Indexed: 12/14/2022] Open
Abstract
Familial dysautonomia (FD) is a recessive neurodegenerative disease caused by a splice mutation in Elongator complex protein 1 (ELP1, also known as IKBKAP); this mutation leads to variable skipping of exon 20 and to a drastic reduction of ELP1 in the nervous system. Clinically, many of the debilitating aspects of the disease are related to a progressive loss of proprioception; this loss leads to severe gait ataxia, spinal deformities, and respiratory insufficiency due to neuromuscular incoordination. There is currently no effective treatment for FD, and the disease is ultimately fatal. The development of a drug that targets the underlying molecular defect provides hope that the drastic peripheral neurodegeneration characteristic of FD can be halted. We demonstrate herein that the FD mouse TgFD9;IkbkapΔ20/flox recapitulates the proprioceptive impairment observed in individuals with FD, and we provide the in vivo evidence that postnatal correction, promoted by the small molecule kinetin, of the mutant ELP1 splicing can rescue neurological phenotypes in FD. Daily administration of kinetin starting at birth improves sensory-motor coordination and prevents the onset of spinal abnormalities by stopping the loss of proprioceptive neurons. These phenotypic improvements correlate with increased amounts of full-length ELP1 mRNA and protein in multiple tissues, including in the peripheral nervous system (PNS). Our results show that postnatal correction of the underlying ELP1 splicing defect can rescue devastating disease phenotypes and is therefore a viable therapeutic approach for persons with FD.
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8
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Won E, Palma JA, Kaufmann H, Milla SS, Cohen B, Norcliffe-Kaufmann L, Babb JS, Lui YW. Quantitative magnetic resonance evaluation of the trigeminal nerve in familial dysautonomia. Clin Auton Res 2019; 29:469-473. [PMID: 30783821 DOI: 10.1007/s10286-019-00593-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 01/21/2019] [Indexed: 11/29/2022]
Abstract
PURPOSE Familial dysautonomia (FD) is a rare autosomal recessive disease that affects the development of sensory and autonomic neurons, including those in the cranial nerves. We aimed to determine whether conventional brain magnetic resonance imaging (MRI) could detect morphologic changes in the trigeminal nerves of these patients. METHODS Cross-sectional analysis of brain MRI of patients with genetically confirmed FD and age- and sex-matched controls. High-resolution 3D gradient-echo T1-weighted sequences were used to obtain measurements of the cisternal segment of the trigeminal nerves. Measurements were obtained using a two-reader consensus. RESULTS Twenty pairs of trigeminal nerves were assessed in ten patients with FD and ten matched controls. The median (interquartile range) cross-sectional area of the trigeminal nerves in patients with FD was 3.5 (2.1) mm2, compared to 5.9 (2.0) mm2 in controls (P < 0.001). No association between trigeminal nerve area and age was found in patients or controls. CONCLUSIONS Using conventional MRI, the caliber of the trigeminal nerves was significantly reduced bilaterally in patients with FD compared to controls, a finding that appears to be highly characteristic of this disorder. The lack of correlation between age and trigeminal nerve size supports arrested neuronal development rather than progressive atrophy.
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Affiliation(s)
- Eugene Won
- Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, 10016, USA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, 10016, USA.
| | - Sarah S Milla
- Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA.,Department of Radiology, Emory University School of Medicine, Atlanta, GA, USA
| | - Benjamin Cohen
- Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA
| | | | - James S Babb
- Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Yvonne W Lui
- Department of Radiology, New York University School of Medicine, New York, NY, 10016, USA.
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9
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Kazachkov M, Palma JA, Norcliffe-Kaufmann L, Bar-Aluma BE, Spalink CL, Barnes EP, Amoroso NE, Balou SM, Bess S, Chopra A, Condos R, Efrati O, Fitzgerald K, Fridman D, Goldenberg RM, Goldhaber A, Kaufman DA, Kothare SV, Levine J, Levy J, Lubinsky AS, Maayan C, Moy LC, Rivera PJ, Rodriguez AJ, Sokol G, Sloane MF, Tan T, Kaufmann H. Respiratory care in familial dysautonomia: Systematic review and expert consensus recommendations. Respir Med 2018; 141:37-46. [PMID: 30053970 PMCID: PMC6084453 DOI: 10.1016/j.rmed.2018.06.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/14/2018] [Accepted: 06/18/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Familial dysautonomia (Riley-Day syndrome, hereditary sensory autonomic neuropathy type-III) is a rare genetic disease caused by impaired development of sensory and afferent autonomic nerves. As a consequence, patients develop neurogenic dysphagia with frequent aspiration, chronic lung disease, and chemoreflex failure leading to severe sleep disordered breathing. The purpose of these guidelines is to provide recommendations for the diagnosis and treatment of respiratory disorders in familial dysautonomia. METHODS We performed a systematic review to summarize the evidence related to our questions. When evidence was not sufficient, we used data from the New York University Familial Dysautonomia Patient Registry, a database containing ongoing prospective comprehensive clinical data from 670 cases. The evidence was summarized and discussed by a multidisciplinary panel of experts. Evidence-based and expert recommendations were then formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. RESULTS Recommendations were formulated for or against specific diagnostic tests and clinical interventions. Diagnostic tests reviewed included radiological evaluation, dysphagia evaluation, gastroesophageal evaluation, bronchoscopy and bronchoalveolar lavage, pulmonary function tests, laryngoscopy and polysomnography. Clinical interventions and therapies reviewed included prevention and management of aspiration, airway mucus clearance and chest physical therapy, viral respiratory infections, precautions during high altitude or air-flight travel, non-invasive ventilation during sleep, antibiotic therapy, steroid therapy, oxygen therapy, gastrostomy tube placement, Nissen fundoplication surgery, scoliosis surgery, tracheostomy and lung lobectomy. CONCLUSIONS Expert recommendations for the diagnosis and management of respiratory disease in patients with familial dysautonomia are provided. Frequent reassessment and updating will be needed.
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Affiliation(s)
- Mikhail Kazachkov
- Department of Pediatric Pulmonology, New York University School of Medicine, New York, NY, United States; Gastroesophageal, Upper Airway and Respiratory Diseases Center, New York University School of Medicine, New York, NY, United States
| | - Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States
| | - Bat-El Bar-Aluma
- Pediatric Pulmonary Unit, The Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Israel
| | - Christy L Spalink
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States
| | - Erin P Barnes
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States
| | - Nancy E Amoroso
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine. New York University School of Medicine, New York, NY, United States
| | - Stamatela M Balou
- Department of Otolaryngology-Head and Neck Surgery, New York University School of Medicine, New York, NY, United States
| | - Shay Bess
- Department of Orthopedic Surgery, New York University School of Medicine, New York, NY, United States
| | - Arun Chopra
- Department of Pediatrics, Division of Pediatric Critical Care, New York University School of Medicine, New York, NY, United States
| | - Rany Condos
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine. New York University School of Medicine, New York, NY, United States
| | - Ori Efrati
- Pediatric Pulmonary Unit, The Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Israel
| | - Kathryn Fitzgerald
- Department of Pediatric Pulmonology, New York University School of Medicine, New York, NY, United States
| | - David Fridman
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine. New York University School of Medicine, New York, NY, United States
| | - Ronald M Goldenberg
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine. New York University School of Medicine, New York, NY, United States
| | - Ayelet Goldhaber
- Department of Pediatrics, Pediatric Gastroenterology Unit, New York University School of Medicine, New York, NY, United States
| | - David A Kaufman
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine. New York University School of Medicine, New York, NY, United States
| | - Sanjeev V Kothare
- Department of Neurology, Pediatric Sleep Medicine Unit, New York University School of Medicine, New York, NY, United States
| | - Jeremiah Levine
- Department of Pediatrics, Pediatric Gastroenterology Unit, New York University School of Medicine, New York, NY, United States
| | - Joseph Levy
- Department of Pediatrics, Pediatric Gastroenterology Unit, New York University School of Medicine, New York, NY, United States
| | - Anthony S Lubinsky
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine. New York University School of Medicine, New York, NY, United States
| | - Channa Maayan
- Department of Pediatrics. Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Libia C Moy
- Department of Pediatrics, Pediatric Gastroenterology Unit, New York University School of Medicine, New York, NY, United States
| | - Pedro J Rivera
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine. New York University School of Medicine, New York, NY, United States
| | - Alcibiades J Rodriguez
- Department of Neurology, Sleep Laboratory, New York University School of Medicine, New York, NY, United States
| | - Gil Sokol
- Pediatric Pulmonary Unit, The Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Israel
| | - Mark F Sloane
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine. New York University School of Medicine, New York, NY, United States
| | - Tina Tan
- Gastroesophageal, Upper Airway and Respiratory Diseases Center, New York University School of Medicine, New York, NY, United States
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, United States.
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10
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Singh K, Palma JA, Kaufmann H, Tkachenko N, Norcliffe-Kaufmann L, Spalink C, Kazachkov M, Kothare SV. Prevalence and characteristics of sleep-disordered breathing in familial dysautonomia. Sleep Med 2018; 45:33-38. [PMID: 29680425 PMCID: PMC5918267 DOI: 10.1016/j.sleep.2017.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 12/30/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Familial dysautonomia (FD) is an autosomal recessive disorder characterized by impaired development of sensory and afferent autonomic nerves. Untreated sleep-disordered breathing (SDB) has been reported to increase the risk of sudden unexpected death in FD. We aimed to describe the prevalence and characteristics of SDB in FD. PATIENTS/METHODS Seventy-five patients with FD (20 adults and 55 children) underwent in-lab polysomnography, including peripheral capillary oxygen saturation (SpO2) and end-tidal capnography (EtCO2) measurements. A t-test and Spearman's correlation analysis were performed to evaluate the impact of age on sleep, occurrence of apneas, SpO2 and EtCO2 levels; and to determine the relationship between apneas and SpO2/EtCO2 measurements during different sleep stages. RESULTS Overall, 85% of adults and 91% of pediatric patients had some degree of SDB. Obstructive sleep apneas were more severe in adults (8.5 events/h in adults vs. 3.5 events/h in children, p = 0.04), whereas central apneas were more severe (10.8 vs. 2.8 events/h, p = 0.04) and frequent (61.8% vs. 45%, p = 0.017) in children. Overall, a higher apnea-hypopnea index was associated with increased severity of hypoxia and hypoventilation, although in a significant fraction of patients (67% and 46%), hypoxemia and hypoventilation occurred independent of apneas. CONCLUSION Most adult and pediatric patients with FD suffer from some degree of SDB. There was a differential effect of age in the pattern of SDB observed. In some FD patients, hypoventilation and hypoxia occurred independently of apneas. Therefore, we recommend including EtCO2 monitoring during polysomnography in all patients with FD to detect SDB.
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Affiliation(s)
- Kanwaljit Singh
- University of Massachusetts Medical School, Worcester, MA, USA
| | - Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Nataliya Tkachenko
- Department of Pediatrics, New York University Langone Medical Center, New York, NY, USA
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Christy Spalink
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Mikhail Kazachkov
- Department of Pediatrics, New York University Langone Medical Center, New York, NY, USA
| | - Sanjeev V Kothare
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA.
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11
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Rubin BY, Anderson SL. IKBKAP/ELP1 gene mutations: mechanisms of familial dysautonomia and gene-targeting therapies. APPLICATION OF CLINICAL GENETICS 2017; 10:95-103. [PMID: 29290691 PMCID: PMC5735983 DOI: 10.2147/tacg.s129638] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The successful completion of the Human Genome Project led to the discovery of the molecular basis of thousands of genetic disorders. The identification of the mutations that cause familial dysautonomia (FD), an autosomal recessive disorder that impacts sensory and autonomic neurons, was aided by the release of the human DNA sequence. The identification and characterization of the genetic cause of FD have changed the natural history of this disease. Genetic testing programs, which were established shortly after the disease-causing mutations were identified, have almost completely eliminated the birth of children with this disorder. Characterization of the principal disease-causing mutation has led to the development of therapeutic modalities that ameliorate its effect, while the development of mouse models that recapitulate the impact of the mutation has allowed for the in-depth characterization of its impact on neuronal development and survival. The intense research focus on this disorder, while clearly benefiting the FD patient population, also serves as a model for the positive impact focused research efforts can have on the future of other genetic diseases. Here, we present the research advances and scientific breakthroughs that have changed and will continue to change the natural history of this centuries-old genetic disease.
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Affiliation(s)
- Berish Y Rubin
- Department of Biological Sciences, Fordham University, Bronx, NY, USA
| | - Sylvia L Anderson
- Department of Biological Sciences, Fordham University, Bronx, NY, USA
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Palma JA, Spalink C, Barnes EP, Norcliffe-Kaufmann L, Kaufmann H. Neurogenic dysphagia with undigested macaroni and megaesophagus in familial dysautonomia. Clin Auton Res 2017; 28:125-126. [PMID: 29196937 DOI: 10.1007/s10286-017-0487-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 11/21/2017] [Indexed: 11/25/2022]
Affiliation(s)
- Jose-Alberto Palma
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Christy Spalink
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Erin P Barnes
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA.
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13
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Gutiérrez JV, Kaufmann H, Palma JA, Mendoza-Santiesteban C, Macefield VG, Norcliffe-Kaufmann L. Founder mutation in IKBKAP gene causes vestibular impairment in familial dysautonomia. Clin Neurophysiol 2017; 129:390-396. [PMID: 29289840 DOI: 10.1016/j.clinph.2017.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 11/10/2017] [Accepted: 11/16/2017] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To assess vestibular function in patients with familial dysautonomia (FD), a hereditary sensory and autonomic neuropathy - caused by a mutation in the IKBKAP gene (c.2204 + 6 T>C) - and characterized by marked gait ataxia. METHODS Cervical and vestibular evoked myogenic potentials (cVEMPs and oVEMPs) were recorded from the sternocleidomastoid (SCM) and extraocular muscles in 14 homozygous patients, 2 heterozygous patients, and 15 healthy controls during percussion of the forehead. RESULTS cVEMP and oVEMP amplitudes were significantly lower, and peak latencies significantly delayed, in the FD patients. There were no differences in overall EMG during attempted maximal voluntary contractions of the SCM muscle, suggesting intact efferent function. The two heterozygotes with a minor haplotype missense (R696P) mutation in exon 19 of the IKBKAP gene had cVEMP responses less affected than the homozygous. CONCLUSIONS The founder mutation in the IKBKAP gene affects the development of vestibular afferent pathways, leading to attenuated cVEMPs. SIGNIFICANCE Vestibular abnormalities may contribute to the gait ataxia in FD.
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Affiliation(s)
- Joel V Gutiérrez
- Department of Clinical Neurophysiology, Cuban Institute of Neurology and Neurosurgery, La Habana, Cuba
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Jose-Alberto Palma
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | | | - Vaughan G Macefield
- College of Medicine, Mohammed Bin Rashid University of Medicine & Health Sciences, Dubai, United Arab Emirates
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Chaverra M, George L, Mergy M, Waller H, Kujawa K, Murnion C, Sharples E, Thorne J, Podgajny N, Grindeland A, Ueki Y, Eiger S, Cusick C, Babcock AM, Carlson GA, Lefcort F. The familial dysautonomia disease gene IKBKAP is required in the developing and adult mouse central nervous system. Dis Model Mech 2017; 10:605-618. [PMID: 28167615 PMCID: PMC5451171 DOI: 10.1242/dmm.028258] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/23/2017] [Indexed: 02/06/2023] Open
Abstract
Hereditary sensory and autonomic neuropathies (HSANs) are a genetically and clinically diverse group of disorders defined by peripheral nervous system (PNS) dysfunction. HSAN type III, known as familial dysautonomia (FD), results from a single base mutation in the gene IKBKAP that encodes a scaffolding unit (ELP1) for a multi-subunit complex known as Elongator. Since mutations in other Elongator subunits (ELP2 to ELP4) are associated with central nervous system (CNS) disorders, the goal of this study was to investigate a potential requirement for Ikbkap in the CNS of mice. The sensory and autonomic pathophysiology of FD is fatal, with the majority of patients dying by age 40. While signs and pathology of FD have been noted in the CNS, the clinical and research focus has been on the sensory and autonomic dysfunction, and no genetic model studies have investigated the requirement for Ikbkap in the CNS. Here, we report, using a novel mouse line in which Ikbkap is deleted solely in the nervous system, that not only is Ikbkap widely expressed in the embryonic and adult CNS, but its deletion perturbs both the development of cortical neurons and their survival in adulthood. Primary cilia in embryonic cortical apical progenitors and motile cilia in adult ependymal cells are reduced in number and disorganized. Furthermore, we report that, in the adult CNS, both autonomic and non-autonomic neuronal populations require Ikbkap for survival, including spinal motor and cortical neurons. In addition, the mice developed kyphoscoliosis, an FD hallmark, indicating its neuropathic etiology. Ultimately, these perturbations manifest in a developmental and progressive neurodegenerative condition that includes impairments in learning and memory. Collectively, these data reveal an essential function for Ikbkap that extends beyond the peripheral nervous system to CNS development and function. With the identification of discrete CNS cell types and structures that depend on Ikbkap, novel strategies to thwart the progressive demise of CNS neurons in FD can be developed. Summary:Ikbkap is essential for normal CNS development, neuronal survival and behavior, adding to our understanding of the role of the Elongator complex in the mammalian CNS.
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Affiliation(s)
- Marta Chaverra
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Lynn George
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA.,Department of Biological and Physical Sciences, Montana State University Billings, Billings, MT 59101, USA
| | - Marc Mergy
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Hannah Waller
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Katharine Kujawa
- Department of Psychology, Montana State University, Bozeman, MT 59717, USA
| | - Connor Murnion
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Ezekiel Sharples
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Julian Thorne
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA.,University of Washington, School of Medicine, Seattle, WA 98195, USA
| | - Nathaniel Podgajny
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | | | - Yumi Ueki
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Steven Eiger
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Cassie Cusick
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - A Michael Babcock
- Department of Psychology, Montana State University, Bozeman, MT 59717, USA
| | | | - Frances Lefcort
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
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15
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Chelimsky G, Chelimsky T. Unusual Structural Autonomic Disorders Presenting in Pediatrics: Disorders Associated with Hypoventilation and Autonomic Neuropathies. Pediatr Clin North Am 2017; 64:173-183. [PMID: 27894444 DOI: 10.1016/j.pcl.2016.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Structural autonomic disorders (producing structural damage to the autonomic nervous system or autonomic centers) are far less common than functional autonomic disorders (reflected in abnormal function of a fundamentally normal autonomic nervous system) in children and teenagers. This article focuses on this uncommon first group in the pediatric clinic. These disorders are grouped into 2 main categories: those characterized by hypoventilation and those that feature an autonomic neuropathy.
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Affiliation(s)
- Gisela Chelimsky
- Division of Pediatric Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Thomas Chelimsky
- Department of Neurology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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16
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Hilz MJ, Moeller S, Buechner S, Czarkowska H, Ayappa I, Axelrod FB, Rapoport DM. Obstructive Sleep-Disordered Breathing Is More Common than Central in Mild Familial Dysautonomia. J Clin Sleep Med 2016; 12:1607-1614. [PMID: 27655467 DOI: 10.5664/jcsm.6342] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 07/19/2016] [Indexed: 01/22/2023]
Abstract
STUDY OBJECTIVES In familial dysautonomia (FD) patients, sleep-disordered breathing (SDB) might contribute to their high risk of sleep-related sudden death. Prevalence of central versus obstructive sleep apneas is controversial but may be therapeutically relevant. We, therefore, assessed sleep structure and SDB in FD-patients with no history of SDB. METHODS 11 mildly affected FD-patients (28 ± 11 years) without clinically overt SDB and 13 controls (28 ± 10 years) underwent polysomnographic recording during one night. We assessed sleep stages, obstructive and central apneas (≥ 90% air flow reduction) and hypopneas (> 30% decrease in airflow with ≥ 4% oxygen-desaturation), and determined obstructive (oAI) and central (cAI) apnea indices and the hypopnea index (HI) as count of respective apneas/hypopneas divided by sleep time. We obtained the apnea-hypopnea index (AHI4%) from the total of apneas and hypopneas divided by sleep time. We determined differences between FD-patients and controls using the U-test and within-group differences between oAIs, cAIs, and HIs using the Friedman test and Wilcoxon test. RESULTS Sleep structure was similar in FD-patients and controls. AHI4% and HI were significantly higher in patients than controls. In patients, HIs were higher than oAIs and oAIs were higher than cAIs. In controls, there was no difference between HIs, oAIs, and cAIs. Only patients had apneas and hypopneas during slow wave sleep. CONCLUSIONS In our FD-patients, obstructive apneas were more common than central apneas. These findings may be related to FD-specific pathophysiology. The potential ramifications of SDB in FD-patients suggest the utility of polysomnography to unveil SDB and initiate treatment. COMMENTARY A commentary on this article appears in this issue on page 1583.
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Affiliation(s)
- Max J Hilz
- Department of Neurology, University of Erlangen-Nürnberg, Erlangen, Germany.,Autonomic Unit, University Colloge of London, Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Sebastian Moeller
- Department of Neurology, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Susanne Buechner
- Department of Neurology, General Hospital of Bozen/Bolzano, Bozen/Bolzano, Italy
| | - Hanna Czarkowska
- Cushing Neuroscience Institute, NS-LIJ Health System, Great Neck, NY
| | - Indu Ayappa
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, NY
| | - Felicia B Axelrod
- Dysautonomia Center, New York University Langone School of Medicine, New York, NY
| | - David M Rapoport
- Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, NY
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Dietrich P, Dragatsis I. Familial Dysautonomia: Mechanisms and Models. Genet Mol Biol 2016; 39:497-514. [PMID: 27561110 PMCID: PMC5127153 DOI: 10.1590/1678-4685-gmb-2015-0335] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/16/2016] [Indexed: 11/22/2022] Open
Abstract
Hereditary Sensory and Autonomic Neuropathies (HSANs) compose a heterogeneous group of genetic disorders characterized by sensory and autonomic dysfunctions. Familial Dysautonomia (FD), also known as HSAN III, is an autosomal recessive disorder that affects 1/3,600 live births in the Ashkenazi Jewish population. The major features of the disease are already present at birth and are attributed to abnormal development and progressive degeneration of the sensory and autonomic nervous systems. Despite clinical interventions, the disease is inevitably fatal. FD is caused by a point mutation in intron 20 of the IKBKAP gene that results in severe reduction in expression of IKAP, its encoded protein. In vitro and in vivo studies have shown that IKAP is involved in multiple intracellular processes, and suggest that failed target innervation and/or impaired neurotrophic retrograde transport are the primary causes of neuronal cell death in FD. However, FD is far more complex, and appears to affect several other organs and systems in addition to the peripheral nervous system. With the recent generation of mouse models that recapitulate the molecular and pathological features of the disease, it is now possible to further investigate the mechanisms underlying different aspects of the disorder, and to test novel therapeutic strategies.
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Affiliation(s)
- Paula Dietrich
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
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18
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Norcliffe-Kaufmann L, Slaugenhaupt SA, Kaufmann H. Familial dysautonomia: History, genotype, phenotype and translational research. Prog Neurobiol 2016; 152:131-148. [PMID: 27317387 DOI: 10.1016/j.pneurobio.2016.06.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 01/30/2023]
Abstract
Familial dysautonomia (FD) is a rare neurological disorder caused by a splice mutation in the IKBKAP gene. The mutation arose in the 1500s within the small Jewish founder population in Eastern Europe and became prevalent during the period of rapid population expansion within the Pale of Settlement. The carrier rate is 1:32 in Jews descending from this region. The mutation results in a tissue-specific deficiency in IKAP, a protein involved in the development and survival of neurons. Patients homozygous for the mutations are born with multiple lesions affecting mostly sensory (afferent) fibers, which leads to widespread organ dysfunction and increased mortality. Neurodegenerative features of the disease include progressive optic atrophy and worsening gait ataxia. Here we review the progress made in the last decade to better understand the genotype and phenotype. We also discuss the challenges of conducting controlled clinical trials in this rare medically fragile population. Meanwhile, the search for better treatments as well as a neuroprotective agent is ongoing.
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Affiliation(s)
| | - Susan A Slaugenhaupt
- Center for Human Genetic Research, Massachusetts General Hospital Research Institute and Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA.
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Mohammadian F, Noroozian M, Nafissi S, Fatehi F. Blink Reflex May Help Discriminate Alzheimer Disease From Vascular Dementia. J Clin Neurophysiol 2015; 32:505-11. [PMID: 26629759 DOI: 10.1097/wnp.0000000000000214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Dementia has several different etiologies, and vascular dementia (VaD) is considered the second leading cause of dementia after Alzheimer disease (AD). Various studies used blink reflex in different spectrum of neurological diseases as a complementary diagnostic test. We performed blink test in AD, VaD, and mixed dementia to investigate different usefulness of blink reflex in differentiating these types of dementia. METHODS Blink reflex was performed for patients with AD (n = 18), VaD (n = 17), mixed dementia (n = 19), and normal subjects (n = 20). The absolute latency of R1, R2, and contralateral R2 (R2c) was determined and then compared with normal values. We used ROC curve to determine the screening cut-off value for R2 and R2c to discriminate dementia with vascular component and AD. RESULTS The mean age ± SD of patients was 71.61 ± 8.23, 66.71 ± 11.48, 75.26 ± 8.32, and 66.60 ± 3.91 years in 4 groups of AD, VaD, mixed dementia, and normal, respectively. R2 and R2c were recorded in fewer number of subjects with VaD or mixed dementia than AD and normal subjects. For mean R2 latency higher than 45 milliseconds, the sensitivity and specificity were 42% and 100%, respectively, and for latency higher than 45 milliseconds, the sensitivity and specificity were 72% and 89%, respectively. CONCLUSIONS R2 and R2c components of blink reflex could specifically discriminate between Alzheimer and dementia with vascular component. The interruption of descending corticoreticular pathways by small infarcts could explain it.
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Affiliation(s)
- Fatemeh Mohammadian
- *Department of Neurology, Shariati Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; †Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran; and ‡Iranian Center of Neurological Research, Department of Neurology, Shariati Hospital, School of medicine, Tehran University of Medical Sciences, Tehran, Iran
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Fuente Mora C, Norcliffe-Kaufmann L, Palma JA, Kaufmann H. Chewing-induced hypertension in afferent baroreflex failure: a sympathetic response? Exp Physiol 2015; 100:1269-79. [PMID: 26435473 PMCID: PMC5074388 DOI: 10.1113/ep085340] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 09/01/2015] [Indexed: 12/29/2022]
Abstract
NEW FINDINGS What is the central question of this study? Our goal was to understand the autonomic responses to eating in patients with congenital afferent baroreflex failure, by documenting changes in blood pressure and heart rate with chewing, swallowing and stomach distension. What is the main finding and its importance? Patients born with lesions in the afferent baroreceptor pathways have an exaggerated pressor response to food intake. This appears to be a sympathetically mediated response, triggered by chewing, that occurs independently of swallowing or distension of the stomach. The chewing-induced pressor response may be useful as a counter-manoeuvre to prevent orthostatic hypotension in these patients. Familial dysautonomia (FD) is a rare genetic disease with extremely labile blood pressure resulting from baroreflex deafferentation. Patients have marked surges in sympathetic activity, frequently surrounding meals. We conducted an observational study to document the autonomic responses to eating in patients with FD and to determine whether sympathetic activation was caused by chewing, swallowing or stomach distension. Blood pressure and R-R intervals were measured continuously while chewing gum (n = 15), eating (n = 20) and distending the stomach by percutaneous endoscopic gastrostomy tube feeding (n = 9). Responses were compared with those of normal control subjects (n = 10) and of patients with efferent autonomic failure (n = 10) who have chronically impaired sympathetic outflow. In patients with FD, eating was associated with a marked but transient pressor response (P < 0.0001) and additional signs of sympathetic activation, including tachycardia, diaphoresis and flushing of the skin. Chewing gum evoked a similar increase in blood pressure that was higher in patients with FD than in control subjects (P = 0.0001), but was absent in patients with autonomic failure. In patients with FD, distending the stomach by percutaneous endoscopic gastrostomy tube feeding failed to elicit a pressor response. The results provide indirect evidence that chewing triggers sympathetic activation. The increase in blood pressure is exaggerated in patients with FD as a result of blunted afferent baroreceptor signalling. The chewing pressor response may be useful as a counter-manoeuvre to raise blood pressure and prevent symptomatic orthostatic hypotension in patients with FD.
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Affiliation(s)
- Cristina Fuente Mora
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Lucy Norcliffe-Kaufmann
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Jose-Alberto Palma
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Horacio Kaufmann
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, NY, USA
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Evidence of brainstem dysfunction in patients with familial dysautonomia and carriers of the IKBKAP mutation. Clin Neurophysiol 2015; 127:1748-1749. [PMID: 26525363 DOI: 10.1016/j.clinph.2015.08.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 08/25/2015] [Accepted: 08/31/2015] [Indexed: 11/20/2022]
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22
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Brainstem reflexes in familial dysautonomia. Reply to "Evidence of brainstem dysfunction in patients with familial dysautonomia and carriers of the IKBKAP mutation". Clin Neurophysiol 2015; 127:1749-1750. [PMID: 26529998 DOI: 10.1016/j.clinph.2015.10.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 10/08/2015] [Indexed: 11/21/2022]
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Palma JA, Norcliffe-Kaufmann L, Fuente-Mora C, Percival L, Mendoza-Santiesteban C, Kaufmann H. Current treatments in familial dysautonomia. Expert Opin Pharmacother 2014; 15:2653-71. [PMID: 25323828 PMCID: PMC4236240 DOI: 10.1517/14656566.2014.970530] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Familial dysautonomia (FD) is a rare hereditary sensory and autonomic neuropathy (type III). The disease is caused by a point mutation in the IKBKAP gene that affects the splicing of the elongator-1 protein (ELP-1) (also known as IKAP). Patients have dramatic blood pressure instability due to baroreflex failure, chronic kidney disease, and impaired swallowing leading to recurrent aspiration pneumonia, which results in chronic lung disease. Diminished pain and temperature perception result in neuropathic joints and thermal injuries. Impaired proprioception leads to gait ataxia. Optic neuropathy and corneal opacities lead to progressive visual loss. AREAS COVERED This article reviews current therapeutic strategies for the symptomatic treatment of FD, as well as the potential of new gene-modifying agents. EXPERT OPINION Therapeutic focus on FD is centered on reducing the catecholamine surges caused by baroreflex failure. Managing neurogenic dysphagia with effective protection of the airway passages and prompt treatment of aspiration pneumonias is necessary to prevent respiratory failure. Sedative medications should be used cautiously due to the risk of respiratory depression. Non-invasive ventilation during sleep effectively manages apneas and prevents hypercapnia. Clinical trials of compounds that increase levels of IKAP (ELP-1) are underway and will determine whether they can reverse or slow disease progression.
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Affiliation(s)
- Jose-Alberto Palma
- New York University School of Medicine, Dysautonomia Center, Department of Neurology , 530 First Avenue, Suite 9Q New York, NY 10016 , USA +1 212 263 7225 ;
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